As disturbing as the Ontario government's spending plans may be, it is important to keep a sense of perspective as to their real implications. Comparisons with France or Canada a decade ago are overdrawn - this is, remember, a provincial government, with less latitude for fiscal foolishness. For which, given the primitive economic thinking displayed in the budget, may the Lord make us truly thankful.

So the NDP's first budget, notwithstanding its record $9.7-billion deficit, is not going to fuel higher inflation, any more than the six budgets of the Liberals before them did. Governments create inflation not by selling public debt, but by buying it - or rather, by prevailing upon central banks to do so. Whatever the province's residents may believe, Ontario is not Canada, and could not exercise such power.

Since it cannot monetize its debts, a provincial government is both a better and a worse credit risk than a national government. Worse, because it has no last recourse to the printing press if it cannot otherwise pay its bills. Better, because it therefore cannot also cheat its creditors by inflation. The crisis that forced the Mitterrand government to abandon its early ''dash for growth'' was initiated by a collapse of the franc. The C$ is unlikely to perform a similar swandive - at least, not immediately.

As large as the deficit is, it is nothing like the kind Ottawa posted in the latter years of the Trudeau government and after. The federal deficit has not been less than 4% of gross domestic product since the 1970s. At its peak, in fiscal 1985, it was more than 8%. As each year's borrowing requirement was added, the national debt compounded faster than the economy could grow; the debt-to-GDP ratio has risen accordingly, from 30% a decade ago to almost 60% today.

At its worst, the Ontario deficit is projected to be about 3.4% of provincial GDP, declining to little more than 2%, or $7.8 billion, in fiscal 1995. This is less than the provincial economy is expected to grow, meaning the debt-to-GDP ratio will fall. (The trends are certainly different, however. The NDP budget does not project beyond 1995. But it seems likely that somewhere around 1996, the federal deficit, forecast at $6.5 billion, will dip below that of Ontario.)

The deficits are different in origin as well. As much as the Tories like to blame the profligate spending of the Liberals, Ottawa's fiscal difficulties stem at least as much from a collapse in revenues. This was partly recession-driven, as now, but also owed a great deal to the many loopholes then in the tax system, through which revenues hemorrhaged at an alarming rate. Thanks to Michael Wilson's tax reforms, that is much less of a problem today - which benefits the Ontario treasury as much as the feds.

This is not to say that Ontario's fiscal recklessness is without ill effect. To the extent that it adds to Canada's foreign borrowing, it continues to push up the C$ in the short term. This hurts not only Ontario, but the rest of Canada. And to the extent that economic difficulties in the country at large are thought likely to undermine the Bank of Canada's anti-inflationary resolve, and hence increase the chances of a C$ decline in the long term, this can only add to the risk premium lenders demand on interest rates.

Which raises an interesting constitutional point. It is taken for granted in Europe that monetary union will imply considerable restraints on the fiscal policies of member states. The notion that governments within a single currency area could go on spending as they pleased, without regard for the costs imposed on others, is simply not contemplated. So it is envisaged that the European authorities would be given the power to review national budgets.

We in Canada already have a monetary union, of some antiquity. And yet neither the federal government nor the other provinces can do anything to restrain Ontario's wild designs, beyond public complaints and private pleading. Even among sovereign nations, this is less and less acceptable: witness the periodic attempts by the G-7 industrialized countries to co-ordinate policy. Perhaps some may hope for a first ministers' conference to do the same. But consensus is a poor way of ordering human affairs: witness again the G-7's manifest failure.

Governments, as much as individuals, can be relied upon to do what's right only when it is in their own interest - and competition generally makes it so. There is some scope for that here: governments in other provinces are already lifting a lamp for tax-weary firms from Ontario. But if that will not work - and it seems it won't - then a higher authority is needed, to bring the offending government into line. That authority should be vested in Ottawa.